By the time Father William Dunn was appointed pastor last month at St. John Chrysostom in West Roxbury, he had already been through a couple of very different careers.

The first, short-lived one, in his hometown of Lead, South Dakota, during high school and college days, was running an ore train in a gold mine. Father Dunn now refers to that experience as "a great incentive to get an education to get out of there."

The second was his 25 1/2 years as a practicing physician and teacher of medicine in St. Louis and Washington, DC.

Father Dunn entered Blessed John XXIII Seminary in Weston in 2002, and was ordained by Cardinal Sean O'Malley in 2006. After his deacon year at St. Francis of Assisi Parish in Braintree, and a 4 1/2 –year stint as parochial vicar at St. Mary Parish in Chelmsford, he officially started his post at St. John Chrysostom on December 12.

Ed Symkus spoke with Father Dunn about his past, present and future.

After graduating from Dean High School, you went to Creighton University, which is a Jesuit school. Did you plan to work in a religious setting?

Initially, yes, coming from an Irish Catholic family. I'm one of eight, and nuns would always say, "It would be nice if one of you kids ..." So I guess the seed was planted a long time ago.

How did you happen to get into medicine?

My father was a pharmacist, and we all worked at his pharmacy. He didn't have eight children; he had eight indentured servants. But there was always an emphasis on education. I have a brother who's a doctor, another brother who's a pharmacist, and two of my sisters are nurses.

What led you to leave medicine and go into the priesthood?

I never got married. I think I married medicine. It was a jealous mistress. I was just attracted to the church. Maybe it was always there. I was never disillusioned by medicine, and I wasn't tired of it. I was just ready to move on. The only thing I miss is the patients. I don't miss the regulations or the politics or the paperwork. You can have all of that.

How did you end up in all of these different parishes in Massachusetts?

I did my residency in Worcester and kind of fell in love with New England. I had friends in Boston and I would keep coming back to visit.

Was there any specific reason you attended the seminary in Weston?

It's a national seminary, but it's specifically for second career vocations.

What brought you to West Roxbury?

I was in Chelmsford, and there was some noise about moving me. A couple of parishes came open, I thought this one was interesting, partly because it was part of Boston. I'm a city person; I like concrete under my feet. So I made an inquiry. I put my name in for it, called the director of personnel, then I went in and we talked about it. And the cardinal appointed me. I officially started on December 12, and I came here on December 13 after rush hour. I moved into the rectory on the Thursday before that, and I'm still surrounded by boxes and chaos.

Did you know much about West Roxbury?

A little bit. One of my classmates from seminary is from here, and I have friends in J.P. and Chestnut Hill.

How many communities are served by this church?

We have 1,300 families who come from West Roxbury, Roslindale, and Hyde Park. Mayor Menino comes here.

Is a new pastor allowed to make his own mark when he comes to a new church?

You can't do anything liturgically outrageous or against canon law. But I have certain little things I like to do. I say a prayer before Mass that they had never done here before, and I'm going to bring back the bells at Mass during the consecration.

The church is named after St. John Chrysostom, who was the Bishop of Constantinople. Do you know much about him?

He was a great speaker. His homilies would go on for over two hours. Can you imagine that?

Do you plan to do two-hour sermons?

Oh, no. But I will do some programs here. I'll do a couple of talks on the issues of the end of life. The bioethics of death and dying, from both a priest's point of view and a physician's point of view.

Do you manage to find any downtime?

When I was in Washington, I really took advantage of the Kennedy Center. I went to the National Symphony and the opera. Here I'm looking forward to the BSO. I love to listen to classical music. I should probably download all of my discs on an iPod.